I.V. catheters are primarily used to administer fluids, sometimes containing medications, directly into a patient's vascular system. The catheter is inserted into a patient's vein by a health care worker by using a handheld placement device that includes a sharp tip needle. The needle is positioned in the interior hollow portion of the catheter with its tip extended slightly beyond the edge of the catheter. The end of the apparatus opposite the needle tip is made up of the needle connected to a needle hub which is capable of being held by the health care worker during the insertion procedure.
The insertion procedure contains four basic steps: (1) the health care worker inserts the needle and catheter together into the patient's vein; (2) after insertion into the vein with the needle point, the catheter is forwarded into the vein of the patient by the health care worker pushing the catheter with his or her finger; (3) the health care worker withdraws the needle by grasping the hub end (opposite the point end) while at the same time applying pressure to the patient's skin at the insertion site with his or her free hand; and (4) the health care worker then tapes the now inserted catheter to the patient's skin and connects the exposed end of the catheter, the catheter hub, to the source of the fluid to be administered into the patient's vein.
The problem is that immediately after the withdrawal of the needle from the patient's vein, the health care worker who is, at this time involved in at least two urgent procedures must place the exposed needle tip at a nearby location and address the tasks required to accomplish the needle withdrawal. It is at this juncture that the exposed needle tip creates a danger of an accidental needle stick or scratch occurring, which leaves the health care worker vulnerable to the transmission of dangerous blood-borne pathogens, including AIDS and hepatitis.
This danger to the health care worker from accidental needle sticks has caused an impetus for the development of a safer IV catheter in which the occurrence of such accidental needle sticks is prevented. As a result, numerous different safety catheters have been developed to achieve this result, one of which is disclosed, for example, in Swedish Patent publication SE556318. In these safety IV catheters, upon the withdrawal of the needle from the patient, a protective member is automatically positioned over the exposed needle tip so that accidental contact with the needle tip is prevented.
Among the problems that have been encountered in the use of currently available safety IV catheters is that the protective guard that is positioned over the needle tip after needle removal may itself be moved away from its protective position so that the needle tip is no longer shielded by the needle guard. This may occur, for example, when a force is inadvertently applied to the needle guard, to overcome the retentive force that had previously maintained the protective guard over the needle tip. Other problems associated with the known safety catheter is their relative complexity, high cost, and difficulty of fabrication.